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Title:	Enhanced hydrogen production using dark fermentation and microbial electrolysis cell with nickel-based cathode
Authors:	Ibdal (P79487)
Supervisor:	Wan Ramli Wan Daud, Prof. Dato' Ir. Dr.
Keywords:	Effluent Hydrogen
Issue Date:	11-Apr-2018
Description:	Hydrogen is a promising energy carrier that can be produced from wastewater using low cost, easy to handle, environmentally friendly, green and high performance technology such as the dark fermentation technology (DF), and the new emerging bio-electrochemical technology, the microbial electrolysis cell (MEC). Although DF has been improved from conventional to immobilised cell bioreactors, it still suffers from low hydrogen yield because of its inability to extract further more hydrogen from the organic acids produced alongside hydrogen during DF. In addition, the MEC that has been improved by replacement of precious metal catalysts such as Pt for hydrogen evolution reaction (HER) at the cathode with non-precious metals such as Ni, could be used to extract more hydrogen from the organic acids' in DF effluent. The main objective of this study is to improve hydrogen yield from glucose by combining both the DF in immobilised mixed-culture reactor (IMcR) and the MEC in tandem, and using various Ni based catalysts at the MEC cathode. To achieve this, palm oil mill effluent (POME) sludge is used as the source of the mixed-culture to be inoculated in both the IMcR and the anode chamber of the MEC. Four different materials are used as the cathode of the MEC namely iron nickel foam (Fe-NiF), iron nickel mesh (Fe-NiM), graphite felt deposited with nickel (Ni/GF) and titanium deposited with nickel (Ni/Ti). In order to assess the performance of the cathodes, Pt covered graphite is used as the control cathode. Scanning electron microscopy (SEM) is used to characterise the surface of the immobilised mixed-culture beads and nickel-based cathodes. To evaluate the cathode catalytic performance and internal resistance, linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) tests are used in this study. Performance of both IMcR and MEC nickel-based cathode are evaluated based on the hydrogen production rate (Q), hydrogen yield (YH2), hydrogen recovery (rH2), cathodic recovery (rcat.H2) and energy efficiency (ɳE). QIMcR, YH2-IMcR and ɳIMcR were obtained to be 1403 ± 61 mLH2 L-1 d-1, 304.0 ± 13.2 mL g-1CODinitial (2259 mmol H2 mol-1glucose) and 23.0 ± 1.0 % using 5.0 gL-1 of glucose at 60 oC for 48 h. The MEC with Fe-NiF shows the best performance where QFe-NiF, YH2-Fe-NiF and ɳFe-NiF are obtained to be 500 ± 80 mL H2 L-1 d-1, 470.2 ± 11.2 mLg-1CODinitial (1236 mmol mol-1glucose) and 101 ± 16 % using IMcR effluent at 1.0 V applied voltage and room temperature (26 oC) for 24 h. Total glucoses converted to hydrogen using coupled IMcR and MEC with Fe-NiF is obtained to be 774.2 mLg-1CODinitial (3495 mmol mol-1glucose). Based on these results, the hydrogen yield (mLg-1CODinitial) from glucose can be increase up more than 2 times compared to the IMcR alone. Since the cost of MEC with Fe-NiF is estimated to be USD15.36 per chamber, which is cheaper than USD 25.04 of Pt/GF, so the Fe-NiF cathode can be used as an alternative to Pt in commercial application. The IMcR can be used for hydrogen production from glucose and its effluent also has successfully been used as substrates for generating more hydrogen using MEC nickel-based cathode.,Ph.D.
Pages:	177
Call Number:	TP245.H9I233 2018 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Fuel Cell Institute / Institut Sel Fuel

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